Did a mgp test this weekend from OC to High Desert. 2005 crew cab 5.3L engine, gears 3.73, tires General Grabbers HTS, tire presure 37 psi, gas Costco 87 octane 10% ethenol, Superchips programer set at performance 87 octane, air temp 73 to 84 going and 62 to 55 degrees coming home.Left Friday afternoon at 1430, 60+ miles of stop and go traffic and heavy congestion. 83 miles before I could not set my cruiz control at 68-69 mph.Ya gotta love CA. traffic, engine rpms were turning 2000-2050On the return trip a little less traffic but coming out the desert fighting a 40 mph head wind, this is normal thats what turns all those big wind turbines out side of Palm Springs.Set cruiz control at 66 mph turning 1950-2000 rpms.When I pulled in the driveway trip consisted of 249 miles and my average,fuel economy was 20.9 mpg.With out the stop and go traffic it would have been 21 plus. Now tell me aging why I would want to buy a truck with AFM and 3.08 gears, or a smaller engine. I have had some repairs but I have nothing but praise as to how well this 5.3 with 70500+ performs. jvp

 

Refueled at 426 miles, with the last 177 miles being combo city & CA. fwy.
I let a little more air out of the tires bring them down to 36 psi. Looking for a little
softer ride on CA. roads (most likely the worst in the nation)
Average economy 20.3 on this tank.
jvp

 

I just got back from a 500 mile trip with mine this weekend. About half was highway and the rest was back roads with a lot of slowing and accelerating. I haven't done the hand figuring yet but the DIC says I got 20.3mpg. Not bad but I had hoped for better. It's still the best truck I've ever owned. I wouldn't change a thing about it.

 

CA roads bad???? Ever look close at the Michigan State Flag? It sports a pot hole!